6-Methyl-1,2,3-oxathiazin-4(3H)-one-2,2-dioxide (or an edible cationic salt thereof), conveniently used in the form of its potassium salt (generic name: acesulfame potassium salt), of the formula ##STR1## in combination with 3-(L-aspartyl-D-alaninamido)-2,2,4,4-tetramethylthietane, or 3-(L-aspartyl-D-serinamido)-2,2,4,4-tetramethylthietane, of the formula ##STR2## or an edible salt thereof, provides a combination wherein the bitter aftertaste of acesulfame is masked. At the same time, over a range of concentrations, the combination demonstrates synergism whereby the sweetening power of the combination is greater than its component parts.
Acesulfame, including its potassium salt (hereinafter abbreviated as AS-K), has been described by Clauss et al., U.S. Pat. No. 3,689,486 (1972), as an artificial sweetening agent having a sweetness of 130 relative to cane sugar in water at concentrations equivalent in sweetness to a 4% solution of said cane sugar. Such solutions were further indicated to be free of objectionable bitter taste at the specified concentration (0.031%) equivalent to 4% cane sugar [Clauss et al., Angew. Chemie. Inter. Ed. in English 12 (11), pp. 869-876 (1973)]. However, at concentrations equivalent to 6-10% sucrose, the relative sweetness of AS-K is about 90 or less. Moreover, at concentrations above 6% sucrose equivalent, the bitter chemical taste of AS-K becomes objectionable. Thus its use in edible foods and beverages, in oral hygienic products and in medicinal agents formulated for oral use is greatly limited, since concentrations equivalent to the sweetness of 10% sucrose or better are frequently desirable in such uses.
3-(L-Aspartyl-D-alaninamido)-2,2,4,4-tetramethylthietane, hereinafter called CP-54,802, has been described as a synthetic sweetening agent in European Patent Document No. 34,876, published in 1981. The isolation and purification of this compound in the form of various of its aromatic sulfonate salts has also been described by Sklavounos, U.S. Pat. No. 4,375,430 (March, 1983).
Subsequent to our invention, there has been a new report, unsupported by scientific data, that AS-K is synergistic with aspartame (the methyl ester of L-aspartyl-L-phenylalanine); see Beverage World, April 1983, page 48. There are no known reports concerning the bitter aftertaste of AS-K at higher concentrations, or of methods to overcome that bitter aftertaste.